1. Field of the Invention
The present invention relates generally to protection during hypoxia and fire emergencies and more particularly is concerned with a protective hood and oral/nasal mask for providing breathable air during hypoxia and fire emergencies.
2. Description of the Prior Art
In aircraft fire situations, toxic and noxious gases are typically present in the aircraft. Survivors of recent aircraft fires have stated that one or two breaths of the smoke and noxious gases present in the aircraft fire resulted in the passengers lungs feeling solidified and in the passengers experiencing extreme sleepiness. Passengers of aircraft fires cannot risk taking several breaths of the contaminated, toxic atmospheric air prior to receiving purified air when such immediate and critical symptoms occur from one or two breaths of the noxious and toxic gases. In addition, the noxious gases which are present tend to immediately irritate the passengers eyes, preventing the passenger from seeing and being able to find emergency exits. Also, if the emergency tends to last for an extended period of time, the existent oxygen supplies on the aircraft can be depleted. Many aircraft are equipped with emergency masks for use in case of aircraft decompression. These masks are designed to provide oxygen to air craft occupants very quickly. The present invention combines this hypoxia protection with smoke and fire protection in a single device. The standard hypoxia device provides supplemental oxygen to support respiration but still relies on the aircraft cabin air for additional quantities of air.
PCT International Application No. WO 89/00873 to Brookman discloses a small dropout package containing a protective hood for deployment to enclose the head of the passenger to improve the passenger""s vision in the smoke, a protectable breathing mask for enclosing the mouth and nose of the passenger in order to provide breathable air and a dual air supply system. The Brookman device provides a chemical air purifier having a wet scrubbing system for purifying cabin air of contaminants to supply breathable air to the user.
Brookman discloses using a wet filtering system. The filtering system of Brookman contains a first chamber which contains a sac to store wet base materials until activated by pulling on an actuator. Once activated, the wet base materials scrub the acid gases, which have entered the first chamber, to neutralize such gases. The neutralized gases are then allowed to passed on through a porous membrane to a second chamber having a catalyst disposed within the second chamber. The porous membrane, however, retains the wet base materials within the first chamber. The wet base materials are released from the sac by the pull of a cord which pulls the sac between a pair of rollers to rupture the sac and displace the wet chemical agent into the first chamber.
The use of the wet filtering system taught by the Brookman reference creates several significant disadvantages and problems during operation of such filtering system. The first disadvantage is the mechanical process required to rupture the sac to release the wet chemical agent. The pulling of the sac is achieved by a cord which is attached at both ends. If either end of the cord is inadvertently or accidently disconnected, the sac will not be ruptured and the wet chemical agent will not be released. Thus, the toxic and noxious gases passing in the first chamber will not be neutralized, but sent to the second chamber in their original harmful state. Additionally, as a liquid scrubber will be released in the first chamber upon rupture of the sac, an additional sealing means has to provided at the rollers to prevent leakage of the liquid out of the first chamber. Such leakage would again allow the gases to pass through the first chamber unneutralized. Another problem with the use of liquid scrubber is that during fire emergencies, concerning high temperatures, there will be concerns regarding the boiling points of the liquid used to neutralize the gases. All of these problems with the filtering system of the Brookman create significant safety concerns during real emergencies. Brookman also fails to provide for a heat absorber. Accordingly, the gas which travels through the catalyst can be at a high and harmful temperature and could cause serious injury to the user of such device.
PCT International Application No. WO 87/01949 to Stewart discloses a breathing apparatus comprising a face mask attached to but detachable from an oxygen supply tube and connected to an inflatable reservoir or bag held in a deflated rolled up condition but releasable to provide when attached and deflated, an oxygen supply system and, when detached and inflated a portable respirator or ventilator in a closed rebreathing system with rebreathing bag and oxygen supply in a microclimate free from noxious or hot gases.
Atmospheric air is prevented from entering the Stewart device, as the Stewart device is merely connected to an oxygen supply. Another disadvantage of Stewart, is the hood fails to provide a protective neck seal, as the reference discloses providing goggles to protect the eyes from noxious gases and very hot air.
Brookman and Stewart both fail to disclose a desiccant material for eliminating fogging which could affect the user""s visibility. In Stewart, the exhaled air passes through a carbon dioxide absorber and inflates the reservoir which becomes a rebreathing bag. The carbon dioxide absorber, extends the time for which rebreathing can take place without dangerous build of carbon dioxide. The carbon dioxide absorber does not acts as an anti-fogging device. In fact, the carbon absorber operates regardless of whether the Stewart device is utilized with a hood or not and is, thus, not attached to the hood.
U.S. Pat. No. 4,583,535 issued to Saffo discloses a protection mask comprising a flexible hood having a head opening for placing said hood over the head of a wearer. The hood is provided with an elastic band sewn to the head opening to close the hood relatively tightly around the user""s neck.
One disadvantage of Saffo, is the engagement of a non-elastic or elastic neck seal is not simply solved with the contact of the neck seal material to the neck. The elastic material must effectively seal long hair, facial hair, decorative apparel for the hair and the neck, and the overall range of anthropometric neck sizes.
The present invention replaces the standard hypoxia device by providing improved hypoxia protection, by filtering the additional cabin air required in a decompression event, and the unique feature of smoke and fire protection by providing (with or without a supply of supplemental oxygen) filtered cabin air in the event of an aircraft fire. Therefore, there exists a need for a dual air supply system providing the user or passenger with either, or both, fresh air from the local supply aircraft""s emergency air source, if provided, or from the contaminated surroundings by filtering the air to remove the toxic gases before reaching the passenger. There also exists a need for a device which can rely entirely upon the ambient air supply to revive the user or passenger with fresh, breathable air from contaminated surrounding air for a temporary period sufficient to escape from the room, the surrounding area or the cabin of an aircraft.
In summary, there exists a need for an aircraft respiratory system incorporating both an oral/nasal mask providing the passenger with fresh, breathable air and a protective hood to protect the passenger from the smoke and noxious gases associated with an aircraft fire for improved passenger visibility. There also exists a need for the air purifier to continue to work after the user detaches himself from the bottled air or the aircraft""s emergency air in order to exit the area, room or aircraft.
It is an object of the present invention to provide an air purifying system that allows the user to breath air from an existing air supply and/or from surrounding atmospheric air.
It is another object of the present invention to provide a protective hood to improve passengers"" visibility for an escape during hypoxia and fire emergencies.
It is yet another object of the present invention to provide an oral mask and smoke hood combination which is compact and can be stored in an overhead passenger service unit of an aircraft which drops down from the service unit during an emergency. These and other objects are provided by an oral/nasal mask and hood combination.
Where provided, the mask is removably attachable to a standard oxygen supply, such as an existing oxygen supply on an aircraft overhead compartment. On aircraft without installed supplemental oxygen systems the unit may be attached to a portable oxygen supply or used without attachment to an oxygen source. The instant invention may be used for smoke and fire protection in non-aircraft environments. The mask contains a five stage filter system to allow the user to breath atmospheric air during an onboard fire or hypoxia emergency, and that protection continues after the mask is detached from the aircraft oxygen supply. Fires on aircraft can produce various products of combustion including CO, CO2, acid gases, cyanide, heat and smoke. An effective mask must reduce many of these products to tolerable levels. In the instant invention, many of these products are removed through a five stage filter. The first removes particulate smoke.
In the second stage of the filtering process, a plurality of zeolite spheres are provided for the filtering out of some toxic gases. The third stage consists of an activated charcoal carbon for the filtering out of many of the remaining gases. At this point most products of combustion would be removed, except for CO and CO2.
The fourth stage consists of a catalyst for converting carbon monoxide to carbon dioxide. This conversion significantly increases the temperature of the gas. Thus, the fifth and final stage of the filtering process consists of a heat absorber for reducing the temperature of the now breathable air to tolerable levels before reaching the user.
A hood is attached to the mask. When not in use the hood is folded compactly around filter portion of the oral/nasal mask and held in place by a retainer. A deployment strap, attached to the hood, is pulled to break the retainer when the hood is needed to be donned. The hood fits over the wearer""s head, neck and shoulder area. An elastic neck seal is attached to the inside of the hood to provide a tight fit around the wearer""s neck and to prevent smoke from reaching and irritating the wearer""s eyes. A transparent lens, to provide visibility to the wearer during an emergency, is provided on the hood adjacent to the wearer""s line of sight.
In accordance with these and other objects which will be apparent hereafter, the instant invention will now be described with particular reference to the accompanying drawings.